Method of preparing unsaturated aldehydes and catalyst therefor



United States Patent "ice 3,369,049 METHOD OF PREPARING UNSATURATED ALDEHYDES AND CATALYST THEREFOR Jamal S. Eden, Akron, Ohio, assignor to The B. F. Good- ;{ich Company, New York, N.Y., a corporation of New ork No Drawing. Filed Jan. 20, 1964, Ser. No. 338,571 11 Claims. (Cl. 260-604) This invention relates to a method for preparing acrolein or methacrolein by the catalytic oxidation of propylene or isobutylene in the presence of a catalyst comprising a copper phosphate, a tellurium compound and a rhenium compound at elevated temperatures, and more particularly pertains to a method of oxidizing propylene or isobutylene to acrolein or methacrolein, respectively, by passing a mixture of the olefin and an oxygen containing gas, with or without water vapor, through a catalyst bed at a temperature of about 300-500" C., wherein the catalyst is a mixture of a copper phosphate, particularly copper pyrophosphate, an inorganic oxygen containing tellurium compound, such as tellurium oxide and a rhenium compound such as rhenium oxide or perrhenic acid. The ratio of copper pyrophosphate to tellurium to rhenium can be 100:10-3011-10. This can be Written empirically as CH2m 2o O T1 Re o, in which P is present as a phosphate.

It is known that propylene can be oxidized to acrolein with copper containing catalysts, but the conversion of the propylene and yield of acrolein are quite low, so that the efficiency is also low. The catalytic oxidation of isobutylene to methacrolein is usually more difficult because of the lack of selectivity of the catalysts normally used for the oxidation of propylene. The presence of two methyl groups adjacent to the double bonds in isobutylene makes the catalytic conversion of the olefin to methacrolein quite difficult. It is therefore unusual to find a catalyst which has approximately the same efliciency for oxidizing both olefins mentioned above to the corresponding aldehydes, and which converts isobutylene at a lower temperature than propylene. The preferred temperature for preparing acrolein is 420-475 C. and that for methacrolein is 325-450 C.

With the catalysts of this invention it is possible to obtain efliciencies of up to 61.3 for acrolein and up to 58.3 for methacrolein.

REACTANTS The only essential reactants are oxygen or an oxygen containing gas mixed with an inert gas. The source of oxygen can be relatively pure oxygen, air or a mixture of oxygen diluted with nitrogen so that it contains more than 21% oxygen. Oxygen can also be diluted with other inert gases such as neon, krypton, xenon or helium.

The olefin can be propylene or isobutylene. For the purpose of this invention these olefins can be defined by the generic formula CH3C=CH3 where n=0to1.

The olefins need not be pure. They can contain appreciable amounts of saturated alkanes or other hydrocarbons Without interference with the main reaction, except for the consumption of some oxygen due to oxidation of a portion of the hydrocarbon contaminants.

Water vapor is not an essential ingredient for the reaction, but it does seem to improve yields of the desired aldehyde at any given temperature and it may also act as a heat absorbing medium which tends to aid in temperature control of the reaction.

3,369,049 Patented Feb. 13, 1968 The ratios of reactants can vary between 1-3 mols oxygen and 0-7 mols water vapor per mol of olefin.

THE CATALYST The catalyst is a mixture of a copper phosphate which can be Cu (PO Cu P O or a copper polyphosphate, such as Cu (P O with tellurium oxide and a rhenium oxide which can be perrhenic acid or Re O The molar ratio of ingredients can vary between about 100 for a phosphate, 10-30 for TeO and 1-10 for HReO or a corresponding amount of Re O CATALYST PREPARATION The catalyst can be prepared by several procedures and it can be supported or unsupported.

For fixed bed reactions the catalyst of 10-18 U.S. sieve size is preferred and for fluid bed reactions a US. sieve size of -325 mesh is preferred.

Method I 34.1 g. CuCl -2H O were dissolved in water.

1.6 g. TeO were added to the CuCl solution.

1 g. of HReO dissolved in water was added to the CuCl -TeO mixture.

23.3 g. of H PO were added to the mixture of the above ingredients.

Then 247.8 of a microspheroidal colloidal silica dispersion in water, containing 30-35% by Weight SiO were added to the remaining ingredients. After thorough stirring, the mixture was evaporated to dryness on a steam bath and thereafter baked at 400 C. for about 16 hours. If desired, drying can be effected by a spray-drying technique. The catalyst was then cooled, crushed and screened to the desired sizes.

Methdd II In this procedure the TeO was dissolved in concentrated HCl to form a homogeneous mixture prior to the addition of the H PO Otherwise the steps are the same as in Method I.

Method III Dry, particulate Cu P O- TeO and R6207 are blended and ground in a ball mill to the desired fineness and screened. If a support is desired it can be added to the ball mill with the remaining ingredients.

Method IV REACTION CONDITIONS The reaction is carried out at a temperature of from about 300500 C. and preferably between about 330- 480 C. The best reaction temperature for converting propylene to acrolein is somewhat higher than that for oxidizing isobutylene to methacrolein, but both aldehydes are prepared in most desirable yields and efiiciencies in the range of 330-450 C. for methacrolein and 420- 480 C. for acrolein.

The contact time can range between about 2 to about 70 seconds, but the preferred range is 8 to about 20 seconds. The most desirable contact time will depend in part on the ratios of the reactants and in part on the reaction temperature. The pressure is not critical, it can range from atmospheric to about 100 p.s.i.

EXAMPLE II In this example the catalyst Was composed of a molar ratio of 50 Cu P O 5 TeO and 2 HReO on 620 mols of S The reaction mixture consisted of 1.1 mols of EXAMPLE I 5 oxygen, supplied as air, and 4.4 mols of water vapor per In this example 40 ml. of a catalyst prepared by mol of propylene. The reaction was carried out at 425 C. method I, having a molar ratio of 50 Cu P O 5 TeO in the reactor described above. The cold contact time was and 2 HReO onv 620 mols colloidal silica, were placed in 18.85 seconds. The propylene conversion was 48.7%, the a high silica (Vycor) tube reactor 6 in. long and 22 mm. yield of acrolein was 69.9% for an efiiciency of 34.0%. OD. The reactor was electrically heated by three coils, m one of which extended along the entire length of the re- EXAMPLE In actor and each of the other two coils extended about A series of runs was made using several ratios of 50% of the reactor length. The reactor was preheated to catalyst ingredients and varying ratios of oxygen to proabout 280300 C. and then steam at a temperature of pylene and water vapor to propylene. about 250 C. was admitted through one opening in the The reaction conditions of each run and other pertinent reactor. The requisite amount of propylene was blended data are recorded in the following table:

Catalyst Contact M01 Percent Time, Og/CaHu HzO/CaHs Temp, C. Efiiciency C112P207 T602 H ReOi S10; sec. Propylene Acrolein Conversion Yield 50 15 10 620 11.4 2.1 3.6 450 91. 7 66. 9 61.3 50 15 1 310 10. 5 2. 5 4. 5 420 86. 3 67.8 58. 5 100 1 1, 240 11 1.1 4. 3 445 75. 5 70.1 53. 6 50 15 1 620 12. 5 2. 5 a. 5 420 61. 4 83.0 51. 0 50 10 1 620 9. 3 2. 1 4. 3 440 70. e 72. 5 51. 2 50 5 2 620 18. 3 2.1 5. 1 430 75. 6 60.7 45. 9 50 5 1 s20 14 2. 2 4. 5 435 67. 4 63. 5 42. s 100 10 1 1, 240 9. 6 2. 1 3. 7 460 55. o 75. 5 41. 5 100 1 1, 240 9. a 1. 5 4. 3 450 54. 9 68. 6 37. 7 50 15 1 620 12. 5 2. 5 3.6 420 61. 4 83.0 51. 6 50 15 1 310 10. s 2. 5 4. 5 420 86. 3 57. 8 58. 5 5o 15 1 155 11.0 1. 5 4. 5 440 41. 3 91.0 37. 7

The catalyst shows the molar ratios of ingredients used in its preparation. The contact time is cold contact time.

with the steam just prior to entry into the reactor and oxygen (supplied as air) in the required amount was fed into the reactor through a separate entry port.

The reactor temperature was then raised to the temperature indicated in the table of data below. The contact time is cold contact time, the hot contact time is about 40% of the cold contact time listed.

The eiliuent gases were run through a condenser. The uncondensed gases were passed directly through a vapor phase chromatograph (Perkin-Elmer 154) and analyzed. The condensed liquids were weighed and then vaporized and passed through a vapor phase chromatograph for analysis.

The data obtained in several runs are tabulated below:

EXAMPLE IV EXAMPLE V The catalyst for this run was composed of 05 F 0 15 TeO 1 HReO on 620 mols of ZrO The procedure was the same as already described. The O /C H ratio was H20/C3H5 Contact Time, Temp., 0. M01 Percent M01 Percent M01 Percent Conversion 0 H Yield Acrolein Efiiciency For comparative purposes a mixture of 1.1 mols oxygen (supplied as air) and 4.4 mols of water vapor per mol of propylene was fed into the reactor containing a catalyst composed of 10 rnols Cu P O and 1 mol of TeO The reaction conditions were substantially the same as those of run 1 above. The propylene conversion was 41.7% and the acrolein yield was 56.1 with an efliciency of 23.4%. In another comparative test a catalyst consisting of 25 mols CllgPgOq and 1 mol HReO; was used, with the same feed ratio described immediately above. The reaction temperature was 460 C. The propylene conversion was 41.5%, acrolein yield was 41.5% for an efiiciency of 17.2%. When Cu P O alone was used as the catalyst, using the feed mixture described immediately above and a reaction temperature of 460 C., only 9.4% of the propylene was converted, with a 65.9% yield of acrolein, thus having an eflicicncy of 6.24%.

1.1, H O/C H was 4.3, cold contact time was 11.2 seconds and the reaction temperature was 450 C. This catalyst converted 5 3.2% of the propylene, with a 70% yield of acrolein for an efl'iciency of 37.2%.

EXAMPLE VI Forty ml. of a catalyst comprising 50" mols CllzPgOq, 10 T e0 1 HReO impregnated on 620 mols of a microspheroidal colloidal silica support were placed in the reactor described in Example I. A feed containing a molar ratio of one mol of isobutylene, 2 mols of oxygen, supplied as air, and 4.1 mols of water vapor was passed through a fixed bed of the catalyst at a rate to provide a cold contact time of 9.5 seconds. At 330 C., 93.6% of the isobutylene fed was converted, to yield 56.8% methacrolein, for an efiiciency of 53.2%.

EXAMPLE VII The catalyst of this example had a molar ratio of 50 Cu P O 1s T602, 1 HReO on 310 mols of a microspheroidal colloidal silica. The feed contained a molar ra- 6 a molar basis, 100 Cu P O 10-30 TeO and 1-2 HReO on a silicic support at a temperature of from about 400- 500 C. with a contact time of from about 9 to about 20 seconds, the said reactants on a molar basis comprising tio of one mol isobutylene, 1.5 mols of oxygen, supplied as 5 (a) one mol of propylene, air, and 4.1 mols of water vapor. The feed rate was regu- (b) from about 1 to about 2.5 mols of oxygen suplated to provide a cold contact time of 27.5 seconds. At plied as air, and 7 360 C. all the isobutylene in the feed was converted, to (c) from 0-7 mols of water vapor. yield 58.3% methacrolein. The reactor was then described 5. The method of claim 4 in which the temperature is in Example I and 40 ml. of catalyst were used in a fixed 10 420470 C. and the amount of water vapor is from bed. about 3 to about 5.1 mols per mol of propylene.

EXAMPLE V 6. The method of claim 5 in which the catalyst is The catalyst for this series of runs had a molar ratio fluldlzedf 50 c p g 5 0 and 2 1 0, on 20 mols f 7. The method of claim 5 1n WhlCh the catalyst 1s 1n a Si-O The data, tabulated below, show results obtained 15 fiXed with several oxygen-isobutylene ratios: '8. The method of preparing methacrolein comprising Contact Mol Percent Mol Percent Mol Percent O2/C4H8 Ibo/04m Time, sec. Temp, 0. Conversion Yield Efiiciency C4Hs Methaeroleln Iclai-m: passing a mixture of reactants through a catalyst com- 1. A method of preparing a compound of the formula prising, on a molar basis, 100 CUzPgOq, 10-30 T602 H and 1-2 HReO on a silicic support, at a temperature of (0 2):! 0 from about 300 C. to about 450 C., with a contact time of from about 5 to about 30 seconds, the said rcac-tants on a molar basis comprising H (a) one mol of isobutylene, where n is 0 to 1, comprising contacting a mixture of re- 1 3 mols f oxygen Supplied as air, d actants with catalyst comprising, on a molar basis, 100 of 7 H1015 f water vapor of a pp phosphate, 1040 z and HReOt 011 9. The method of claim 8 in which the temperature a 'y pp at a temperature of from about is between about 330 and 450 C. and the water vapor to about 500 C. with a contact time of from about 5 to is about 3 to about 5 mols per mol f isohutylehe about 50 seconds, the said reactants on a molar basis com- 40 0 The method f claim .3 in which the catalyst is in prising a fixed bed.

( one mole of y of the formula 11. The method of claim 8 in which the catalyst is H fluidized. 1 2).. References Cited (b) sufiicient oxygen containing gas to provide 1-3 UNITED STATES PATENTS mols of oxygen per mol of said hydrocarbon, and 2,496,621 2/ 1950 Deery 252-437 (c) 0-7 mols of water vapor per mol of said hydro- 2,6 7,527 2/ 1953 Connolly et al. 260604 carbon. 2,662,921 1 2/ 1953 Middleton 260604 2, The method of claim 1 in which the copper phos- 2,670,380 2/ 1954 Hadley 260-604 phate is Cu P O 3,044,965 7/1962 Callahan 252-437 3. The method of claim 1 in which the molar ratio of 3,044,966 7/1962 Callahan et al. 252-437 the catalyst is 100 Cu 'P O- 10-30 TeO and 1-2 BERNARD HELFIN, Primary Examiner.

V HR604 4. A method of preparing acrolein comprising passing a mixture of reactants through a catalyst compnsmg, on

LEON ZITVER, Examiner.

R. H. LILES, J. J. SETELIK, Assistant Examiners. 

1. A METHOD OF PREPARING A COMPOUND OF THE FORMULA 